The present invention relates to a data transfer control device, electronic equipment, and a data transfer control method.
The universal serial bus (USB) standard has recently attracted attention as an interface standard for connections between personal computers and peripheral equipment (broadly speaking: electronic equipment). This USB standard has the advantage of enabling the use of connectors of the same standard to connect peripheral equipment such as a mouse, keyboard, and printer, which are connected by connectors of different standards in the prior art, and of making it possible to implement plug-and-play and hot-plug features.
In comparison with the IEEE 1394 standard, which is also attracting notice as a standard for the same serial bus interface, this USB standard has a problem in that the transfer speed thereof is slower.
In this case, attention is focussed on the decision to use the USB 2.0 standard which can implement a data transfer speed of 480 Mbps (in (high speed) HS mode), far faster than that of the previous USB 1.1 standard, while maintaining backward compatibility with USB 1.1.
With USB 2.0, data transfer is performed at 480 Mbps in high-speed (HS) mode. It therefore has the advantage of enabling its use as an interface for a storage device such as a hard disk drive or optical disk drive, which requires fast transfer speeds.
However, this means that the data transfer control device connected to the USB bus has to process the data that is transferred at the high speed of 480 Mbps. If the processing speed of the data transfer control device or the firmware (CPU) that controls the data transfer control device is slow, it is not possible to ensure the effective transfer speed and a problem occurs in that the bus zone could be lost.